A conventionally known crimp terminal includes a plurality of crimping pieces alternately arranged while being displaced from each other in a lengthwise direction to crimp a connected portion of an electric wire (see JP 2010-073346 A). Specifically, the crimp terminal includes, as shown in FIG. 13, a terminal connector 101 to which a mating terminal or the like is connected, and an electric wire connector 102 that is continuously formed with the terminal connector 101 and to which an electric wire is connected (crimped).
The electric wire connector 102 includes a bottom section 1021 extending in the same direction as that in which the core wire is arranged (a first direction), a plurality of first side crimping pieces 1022 extending from a first side edge in a second direction orthogonal to the first direction of the bottom section 1021, and a plurality of second side crimping pieces 1023 extending from a second side edge in the second direction of the bottom section 1021. The first side crimping pieces 1022 and the second side crimping pieces 1023 are alternately arranged while being displaced from each other in the first direction.
In the crimp terminal 100, the core wire exposed in a tip portion of the electric wire is arranged on the bottom section 1021, and the first side crimping pieces 1022 and the second side crimping pieces 1023 are crimped to embrace the core wire, which causes the core wire to be press-contacted to the bottom section 1021 (see FIG. 14). The electric wire is connected to the crimp terminal in this way.
The electric wire connector 102 of the crimp terminal 100 configured as above has a larger area of contact between the core wire and the crimping pieces than an electric wire connector in which pairs of crimping pieces 1022A and 1023A, each of which is arranged at the same position in the first direction, are arranged at intervals in the first direction, as shown in FIG. 15. This configuration sufficiently provides a force to retain the electric wire by the electric wire connector 102, or in other words, causes the crimped electric wire to be pulled out of the electric wire connector 102 when the electric wire is pulled in a pulling direction (i.e. pull-out strength), under the conditions where the crimping pieces are crimped with a reduced force.
Thus, the crimp terminal 100 can be used for an electric wire having a core wire made of soft metal, such as an aluminum wire, i.e. an electric wire that is likely to be broken with an increased crimping force.
In recent years, there have been some cases where an electric wire having a core wire made not of metal but of conductive fibers such as carbon fibers must be used due to restrictions imposed in certain applications thereof.
When such an electric wire is connected to the crimp terminal, the conductive fibers therein are less likely to be internally stressed at the time of applying pressures. Therefore, in order to obtain a retaining force at a portion to which such an electric wire is connected, crimping must be made with a greater pressing force than the case where the electric wire having the metal core wire that is more likely to be internally stressed is connected. Moreover, for such an electric wire, extremely thin conductive fibers (for example, about several micrometers) are used. Therefore, even if the abovementioned crimp terminal 100 is used, the conductive fibers are still likely to be broken at the time of crimping the crimping pieces 1022, 1023; thus, the crimp terminal 100 connected to the electric wire fails to obtain sufficient pull-out strength.